Basic Application Of Ball Screws
As a high-precision transmission component, ball screw mechanism is widely used in CNC machine tools, automatic heart electronic precision machinery supply mechanism, servo robot, industrial assembly robot, semiconductor production equipment, food processing and packaging, medical equipment and other fields.
If the ball screw mechanism is longitudinally separated, it can be seen that it is mainly composed of a screw, a nut, a ball, a ball return pipe, etc.
The functions of each part of the structure are as follows:
The screw is a rotating part, which is a threaded shaft with high straightness and a semi-circular helical groove, which is the raceway for the ball to roll. The screw has a high hardness and is usually ground after case hardening to ensure excellent wear resistance. The screw is usually connected with the driving part, and the rotation of the screw is directly or indirectly driven by the motor. The direct connection method can be used, that is, the transmission ratio of the motor output shaft and the screw connection is 1 through a special elastic coupling; the motor output shaft and the screw shaft can also be connected through other transmission links, such as synchronous belts, gears, etc.
(2) Nuts.
The nut is used to fix the load that needs to be moved, and its function is similar to the slider of the linear guide mechanism. Generally speaking, various loads that need to be moved (such as worktable, moving slider) are connected with the nut, and the nut that installs various actuators on the worktable or moving slider is processed with a semicircle similar to the nut. The raceway is designed with a return pipe for ball circulation movement. The nut is an important part of the ball screw mechanism. The performance and quality of the ball screw mechanism greatly depend on the nut.
3. Dust-proof sheet.
The function of the dust sheet is to prevent external contaminants from entering the inside of the nut. The ball screw mechanism is a precision part. When using contaminants (dust, debris, metal slag, etc.) into the nut, the ball screw motion pair may be severely worn, reducing the motion accuracy and life of the mechanism, and even damaging the lead screw and other components. Seal the lead screw nut to prevent contamination from entering the nut.
(4) Ball.
In a ball screw mechanism, the function of the balls is the same as in linear guides and linear bearings. As a part of the bearing body, the ball directly bears the load, and at the same time acts as an intermediate transmission element to transmit the motion in a rolling manner. Because it is rolling, there is very little friction.
(5) Oil hole.
The ball screw mechanism needs good lubrication during operation, so lubricating oil or grease should be added regularly. The oil hole is used to add lubricating oil.
The working principle of the ball screw mechanism.
The working principle of the ball screw mechanism is basically the same as the transmission principle of the nut and the screw. Rotate the screw when the screw can rotate and the nut cannot. Since the nut and the load slider are connected with guide parts (such as linear guides and linear bearings), the rotational freedom of the nut is limited, so the nut and the load slider connected to it can only move linearly under the action of the guide parts.